Apparatus for disengaging threaded joints



ZJSLM@ June 19, 1956 R. c. BAKER APPARATUS FOR DISENGAGING THREADEDJOINTS Filed Feb. 23, 1954 United States Patent f()A -APPARATUS FORDSENGAGING THREADE JlNTS Reuben C. Baker, Coalinga, Calif., assigner toBaker Oil Tools, Inc., Los Angeles, Calif., a corporation of .CaliforniaApplication February 23, 1954, Serial No. 411,771I

6 Claims. (Cl. 166-218) latch sleeve is used to accomplish this purpose,discon? nection between the sleeve and well tool being accomplished byrotating the tubular string.

Specic examples of the foregoing arrangement can be found in my PatentNo. 2,644,524, and in my applica-j tion for Non-Rotary ThreadedCoupling, Serial No. 172,925, filed July 10, 1950. As disclosed therein,it is desired to effect a threaded connection between a string of tubingand a well packer or casing collar disposed- The packer or collar has aleft-handin the manner described above, the disconnection being effectedby rotating the tubing string.

At times, after the tubing string has been rotated and disconnected fromthe well tool, the tubing string,

or at least its lower portion, may move inadvertently in a downwarddirection, shifting its threaded latch member bac-k into threaded andcoupled attachment to the well tool. It then becomes necessary to rotatethe tubing string once again to unthread it from the well tool.

It is an object of the present invention to prevent the'l lower portionof the tubular string from inadvertently dropping or moving back intothreaded engagement with a well tool disposed in the well bore, afterthe tubing string has been disconnected fromvthe well tool.

Another object of the invention is to facilitate the unthreading of atubular string from a well tool disposed in a bore hole.

A further object of the invention is to avoid damage to the threads of adetachable threaded connection while the threads are in meshingengagement, and also after the threaded members have been disengagedfrom each other.

This invention possesses many other advantages, and has other objectswhich may be made more clearly apparent from a consideration of a formin which it may be embodied. This form is' shown in the. drawingsaccompanying and forming part of the present specification. It will nowbe described 'in detail, for the purpose of illustrating the generalprinciples of the inventionybut it is tubular body 10 having an upperthreaded box 11, which casing B.

to be understood that such detailed description is not to be taken in alimiting sense, since the scope of the invention is best defined by theappended claims.

Referring to the drawings:

Figure 1 is a combined longitudinal sectional and elevational view of anapparatus disposed in a well casing, with the upper portion of theapparatus attached to a well packer;

Fig. 2 is a View similar to Fig. 1, disclosing the apparatus detachedfrom the well packer;

Fig. `3 is a cross-section, on an enlarged scale, taken along the line 33 of Fig. 1.

As disclosed in the drawings, a well tool A, such as a well packer,which may be of the general type disclosed in the above Patent2,644,524, is disposed in a well It is desired to attach the lowerportion of a running-in or tubular string C to the tool, as well as toeffect a disconnection of the tubular string from the Well tool Wheneverdesired.

As specically shown, the well packer A includes a is preferablyleft-hand. The body of the tool is anchored to the well casing B againstmovement in both directions. Only a portion of the anchoring device isshown in the drawings, this portion preventing upward movement 0f thewell tool within the casing. To accomplish this purpose, an expander 12is disposed on the body 10 and is adapted to wedge within a set of uppersegmental slips 13 that are digging into the wall of the well casing.

A packing sleeve 14 is also disposed around the body 10, having beencompressed into leakproof sealing engagement with both the exterior ofthe body and the wall of the well casing.

Assuming that the well tool or packer A is anchored in packed-olfcondition within the well casing, it is desired to secure a string oftubing C thereto, which extends to the top of the well bore. In view ofthe lefthand threaded box 11 on the body 10 of the well tool, the use ofthe usual type of left-hand thread on the lower portion of the tubularstring would require that the l latter be rotated to the left, in orderto effect its threaded connection to the tool body. For the reasonspointed out above, it is not desirable to rotate the tubular string tothe left. Accordingly, a latching type of coupling D is secured'to thelower portion of the tubular string C,

- it merely being necessary to stab such lower portion into drawings isalso shown in Patent 2,644,524, whereas the specific type is disclosedin above-identied application Serial No. 172,925. The coupling device D,which actually forms the lower end of the tubing string C, in-

v cludes a sub 15a, 15b formed in two parts. An upper sub portion 15a isthreaded onto the upper end of a 19 which collectively have a helicalmale thread 20 provided on their exterior adapted to mate with theinternal female thread 21 at the upper end 11 of the packer body. Thismale thread 20, of course, is left-hand and has the same pitch and leadas the companion female 'thread 21.

One manner of forming the sleeve 16 with its continuous upper portion 17and depending legs 13 and dogs 19 is to first turn the exterior to theproper diameters,

v and then cut the left-hand thread 20 in its external portion. Theexternal thread conforms to the shape and E diameterof the companionthread 21 on the upper end of the packer body. Thereafter, a pluralityof circumferentially spaced, longitudinally extending slots 22 are cutthrough the sleeve from its lower end to its upper portion 1'7, whichremains uncut. This cutting or severing action effectively splits thesleeve and allows its depending legs 1S and dogs 19 to spring inwardlyand outwardly. Normally, the dogs 19 remain in the position that theyoccupy before the slots are cut, to properly meshr with the body boxthread 21. However, the dogs 19 may be retracted sufficiently to allowtheir longitudinal movement into the body without rotation.

In order to allow the dogs 19 to retract to a sufficient extent, so thattheir threaded portion 2l) clears the thread 21 in the body 10, theexterior of the lower sub portion b is relieved, as by forming adownwardly and inwardly converging portion 23, allowing a clearancespace 24 into which the dogs 19 may retract. This relief portionterminates in a retainer or expander portion 25 having a frustoconicalexternal surface diverging in a downward direction and engagingcompanion surfaces 26 at the lower ends of the dogs 19. rl`he distancebetween the tapered expander surface 25 and a lower shoulder 27 on theupper sub portion 15a is substantially greater than the length of thesleeve 16 itself, which allows the sleeve to move longitudinallyrelative to the sub 15a, 15b, for a reason to be described below.

The tubing string C is lowered in the well casing B, with the couplingdevice D at its lower portion. When the upper end of the packer body isreached, the forward or pilot portion 28 of the lower sub enters thebody 1t) until the lowermost thread 20 on the dogs 19 engagesA thecompanion thread 21 in the body box 11. Such engagement precludes, forthe moment, downward movement of the threaded latch sleeve 16 into thebody. However, the lower and upper sub portions 15a, 15b continue tomove downwardly, moving the retainer and expander portion away from thelower ends 26 of the dogs, and bringing the shoulder 27 at the lower endof the upper sub portion 15a into engagement with the upper end of thesleeve 16. Such engagement enables the upper sub portion 15a to forcethe sleeve 16 into the body 10.

It is to be noted that the lower surfaces 20a of the dog thread 20 areinclined in a downward and inward direction, so as to function as camsurging the dogs 19 inwardly when engaging the upper portions of the bodythreads 21. The dogs 19 can retract inwardly, in view of the relief 24provided behind them by the inclining of the lower sub member surface23, and by the movement of the retainer 25 away from the lower ends 26of the dogs 19. Such movement of the sub 15a, 15b and latch sleeve 16into the body box 11 can occur merely as a result of longitudinalmovement of the tubing string C and without its rotation. This downwardmovement into the packer body will continue until the lower end of theretainer 25 engages a body portion 29 immediately below the thread 21,whereupon the dogs 19 can expand outwardly to their initial position,with their collective external thread 2l) in full mesh with thecompanion internal thread 21 in the body box 11.

An upward strain can now be taken on the tubing string C, which shiftsthe upper and lower sub portions 15a, 15b in an upward direction andbrings the retainer 25 against the lower tapered ends 26 of the dogs 19.So long as this strain is maintained, the dogs 19 cannot move inwardly,in View of the backing that the retainer 25 provides against them. As amatter of fact, the retainer acts as an expander, urging the dogs in anoutward direction, to hold their threaded portion 20 fully meshed withthe body box thread 21.

Leakage between the lower sub portion 15b and body 10 may be preventedby mounting suitable side seals 30, in the lower portion of the sub,which engage the inner wall 31 of the body.

When it is desired to disconnect the tubing string C from the well toolA, the former need merely be rotated to the right. This rotationaleffort or torque is transmitted to the dogs 19 of the latch sleeve 16through a plurality of longitudinally extending keys 32 which aresecured to the lower sub member 15b. These keys 32 extend laterallyoutward into the slots 22 between ad jacent dogs 19, being engageablewith the side surfaces of these dogs, As the sub 15a, 15b is rotated,the turning effort is transmitted through the keys 32 to the dogs 19,turning them within the body box 11 and unthreading the dogs 19 and thesleeve 16 in an upward direction from the latter. The turning effort onthe tubing string C to the right is continued until the sleeve dogs 19have been completely unscrewed from the body 10, whereupon the tubingstring may be withdrawn from the well casing B, or elevated therein tothe desired extent.

It is quite evident that the tubing string C can be coupled to the body1G of the well tool merely by moving the former downwardly withoutrotation within the latter, and that uncoupling can occur as a result ofrotating the tubing string to the right. However, under somecircumstances, after the sleeve dogs 19 have been completely unscrewedfrom the body of the tool, the tubing string C, or at least its lowerportion, may be inadvertently moved downwardly again, which will havethe effect of stabbing the latch sleeve 16 back into the body 1l) andrecoupling the tubing string to the body. lt then becomes necessary torotate the tubing string to the right once again, to etect itsuncoupling from the tool A.

The present invention seeks to overcome the foregoing possibility byproviding an apparatus E in the tubular string C which willautomatically elevate the sub 15a, 15b and latch device 16 away from thethreaded body box 11 when the threaded disconnection has taken place. Asdisclosed in the drawings, the upper sub 15a is threadedly connected toan inner tubular member or mandrel 35 telescopically arranged within anouter tubular member or barrel 36 whose upper portion 37a is threadedonto the lower end of a section of the tubing string C, which extends tothe top of the well bore. The inner and outer tubular members 35, 36 areelongated, to enable a substantial amount of relative longitudinalmovement between these parts to occur.

The outer tubular member 36 is composed of an upper section 37a threadedinto the upper end of a lower section 37b, this lower sectionterminating in a lower inturned ange or spring seat 38 against which thelower end of a helical compression spring 39 bears, this springencompassing the inner tubular member or mandrel 35. The upper end ofthe spring bears upon a spring seat or ange 40 formed on the innertubular member 35, the latter having a cylindrical peripheral portion 41extending above the flange 40 which is slidable along the lower innerwall 42 of the upper section 37a of the outer tubular member 36. Leakagefrom the interior of the tubing string C and upper tubular section 37aand downwardly along the cylindrical periphery 41 of the inner mandrelis prevented, as by providing a suitable rubber seal ring 43, in theform of an O ring, in an internal groove 44 in the upper section adaptedto Slidably seal against the cylindrical periphery 41 of the innermandrel member 35.

The outer tubular member 36 may occupy an upper extended position withrespect to the inner mandrel 35, determined by engagement of anintermediate internal stop shoulder 4S on the outer tubular member withthe lower end of the mandrel ange 40. When the parts are in thisposition, the compressed spring 39 is exerting a substantial force onthe inner and outer tubular members 35,V 36 tending to elevate the innermember. The outer tubular member 36 may occupy a lower, or collapsedposition, relative to the inner tubular member 35, which is determinedby engagement of the mandrel ange 40 with a stop shoulder 46 provided bythe lower end of the, upper section 37a of the outer barrel 36.

When the parts are in this last-mentioned position, the spring 39 hasexpanded to a substantial extent, but it is still capable of exerting aforce on the inner and outer members 35, 36 tending to hold them intheir collapsed or contracted position, such as shown in Fig. `2.

The movement of the inner and outer members 35, 36 with respect to eachother is facilitated by minimizing the effect of resistance by fluidsthat might be disposed between the inner and outer members. Thus, one ormore bleeder ports 47 is provided in the outer tubular member 36immediately below the stop shoulder 46, so as to enable fluids in theannulus 48 between the inner and outer members above the mandrel ange 40to pass to the exterior of the apparatus upon upward movement of theange 40 toward the stop shoulder 46. Similarly, one or more bleederports 49 is provided in the outer tubular member 36 immediately abovethe lower spring seat 38, to allow tiuid in the annulus 50 between theinner and outer members below the mandrel flange 40 to move to theexterior of the apparatus, upon relative downward movement of the flange40 toward the lower spring seat 38.

For the purpose of enabling the rotation of the tubular string C to beimparted to the latch sleeve 16, when the latter is to be unthreadedfrom the female body thread 21, a slidable spline connection is providedbetween the inner and outer tubular members 35, 36. Thus, the lower ange38 of the outer tubular member 36 may have one or more keys 51 securedthereto slidable in elongate slots or keyways 52 in the exterior of theinner member 35. It is evident that rotation of the tubing string C istransferred to the outer tubular member 36, and through the key andkeyway connection 51, 52 to the inner tubular member 35, such rotationthen being imparted to the sub a, 15b and through the keys 32 to thedogs 19, for the purpose of unthreading the latter in an upwarddirection from the body 10 of the tool A.

Assuming that the well packer A, or other well tool, has been previouslydisposed in the well casing B, the telescopic apparatus E with thelatching device D mounted on its lower end, is secured to a tubingstring section C and the tubing string then lowered in the well casing.In view of the compressive force of the spring 39, the latter will holdthe mandrel 35 in an upper position with respect to the outertubularvmember 36, limited by the engagement of the flange 40 with theupper stop shoulder 46 on the outer barrel 36, this position beingdisclosed in Fig. 2. The tubing string C and its connecting apparatus E,D forming the lower part thereof are lowered in the well casing B untilthe latching sleeve 16 is stabbed or shifted downwardly within the bodybox 11, a threaded connection being secured between the threaded dogs 19and the box, in the manner described above. If an upward strain is nowtaken on the tubing string C, assurance is had that the dogs 19 will beretained in threaded engagement with the box thread 21. The taking of asuflicient upward strain on the tubular string C will effect a shiftingof the outer barrel 36 upwardly with respect to the inner barrel 35 tothe extent determined by engagement of the intermediate stop shoulder 45with the mandrel ange 4t) (Fig. l). With the parts in this position, thespring 39 has been compressed to a substantial extent.

lt is to be noted that with the telescopic parts occupying theircollapsed position shown in Fig. 2, or their extended position disclosedin Fig. l, the seal ring 43 is continuously in contact with thecylindrical periphery 41 of the mandrel 35, to prevent fluid fromleaking out of the apparatus through the telescopic joint. Fluids maynow pass in either an upward or a downward direction through the tubularstring C and the packer device A vwithout fear of its leaking from theapparatus.

lt' it is desired to disconnect the tubular string C from the well toolA, the tubular string is rotated to the right, the tubular string firstpreferably being elevated, so as to etect a compression of the spring39. The rotation of the tubular string is transmitted to the outerbarrel 36, through the key and keyway connection 51, 52 to the innermandrel 35, and from the latter through the sub 15a, 15b to the keys 32and the dogs 19, rotating the dogs and unscrewing the latter from thebody box 11. As the unthreading action occurs, the latching sleeve 16and the mandrel sub 15a, 15b, as well as the mandrel 35 itself, move inan upward direction, this action being assisted by the expansion of thecompression spring 39. Finally, the dog threads 20 will be completelydisengaged from the box thread 21. When this occurs, the spring canexpand promptly to its fullest extent, lifting the latching sleeve 16completely out of the threaded body portion 11 and a substantialdistance above the latter (Fig. 2). The spring 39 maintains the mandrel35, sub 15a, 15b, and threaded latch sleeve 16 in such an upwardposition, and precludes inadvertent dropping of the sub 15a, 15b andlatch sleeve 16 back into threaded engagement with the female thread 21of the box 11.

The tubing string C, with the inner and outer tubular members 35, 36,sub 15a, 15b and latch sleeve 16 connected thereto, may now be elevatedin the casing B and withdrawn from the well bore, if desired. On theother hand, they can be moved down in the casing to recouple thethreaded dogs 19 to the body thread 21, if this is desired.

With the arrangement disclosed, the unthreading of the dogs 19 from thebody 10 of the well tool is facilitated, since the spring is constantlyurging the inner mandrel 35 and the lower parts attached thereto in anupward direction, which is the direction in which the parts are beingmoved by the latch sleeve 16 when being unscrewed from f the body box11. In addition, damage to the threads is avoided, since the detachmentof the latch sleeve from the uppermost thread of the box immediatelyallows the spring 39 to expand and elevate the latch sleeve Well 16above the box thread 21, and prevents any possibility of v the continuedrotation of the tubing string to cause the lowermost latch sleeve thread20 to rotate along and bounce upon the uppermost body thread 21. Unduestrain on the threads 20, 21 is avoided, since the rotation of thetubing string causes a substantially immediate elevation of the mandrelflange 40 above the intermediate stop shoulder 45, the only forceexerted between the threads being that due to the compression spring 39,which force actually decreases as unthreading proceeds. In the absenceof the device, it is diicult to gauge the upward strain that must betaken on the tubing string C to effect unthreading of the latch sleeve`16 from the box thread 21. Thev tendency is to take too great a strainon the tubing string, which may produce thread damage in and of itself.

The inventor claims:

1. In subsurface apparatus: a well tool having a thread; an upper memberattachable to a running-in string; a lower member telescopically relatedto said upper member; expansible and retractable latch means carried byand movable laterally of said lower member, said latch means having athread companion to said well tool thread and engageable therewith, saidlatch means being movable laterally in one direction on said lowermember into threaded engagement with said well tool thread and laterallyin the other direction on said lower member to an extent suicient toposition said threads out of engagement with each other to enable saidlatch means to be moved longitudinally and without rotation past saidwell tool thread; means providing a connection between said lower memberand latch means for transmitting rotary motion therebetween; meansproviding a connection between said upper and lower members fortransmitting rotary motion therebetween; and means urging said lowermember and latch means in an upward direction relative to said uppermember.

2. n subsurface apparatus: a well tool having a thread;

an upper member attachable to a running-in string; a lower membertelescopically related to said upper member; eX- pansible andretractable latch means carried by and movable laterally of said lowermember, said latch means having a thread companion to said well toolthread and engageable therewith, said latch means being movablelaterally in one direction on said lower member into threaded engagementwith said well tool thread and laterally in the other direction on saidlower member to an extent suicient to position said threads out ofengagement with each other to enable said latch means to be movedlongitudinally and without rotation past said well tool thread; meansproviding a connection between said lower member and llatch means fortransmitting rotary motion therebetween; means providing a connectionbetween said upper and lower members for transmitting rotary motiontherebetween; and spring means acting between said members for urgingsaid lower member and latch means in an upward direction relative tosaid upper member.

3. In subsurface apparatus: a well tool having a thread; an upper memberattachable to a running-in string, a lower member telescopically relatedto said upper member; expansible and retractable latch means carried byand movable laterally of said lower member, said latch means having athread companion to said well tool thread and engageable therewith, saidlatch means being movable laterally in one direction on said lowermember into threaded engagement with said well tool thread and laterallyin the other direction on said lower member to an extent sufficient toposition said threads out of engagement with each other to enable saidlatch means to be moved longitudinally and without rotation past saidwell tool thread; means providing a connection between said lower memberand latch means for transmitting a rotary motion therebetween; meansproviding a connection between said upper and lower members fortransmitting rotary motion therebetween; and a compression springengaging said members to urge said lower member and latch means in anupward direction relative to said upper member.

4. In subsurface apparatus: a well tool having a female thread; an uppermember attachable to a running-in string; a lower member telescopicallyrelated to said upper member; expansible and retractable latch meanscarried by and movable laterally of said lower member, said latch meanshaving a male thread engageable with said female thread, said latchmeans being retractable on said lower member to the extent in which theeffective outer diameter of said male thread is .less than the innerdiameter of said female thread; means providing a connection betweensaid lower member and latch means for transmitting rotary motiontherebetween; means providing a connection between said upper and lowermember for transmitting rotary motion therebetween; and means urgingsaid lower member and latch means in an upward direction relative tosaid upper member.

5. ln subsurface apparatus: a well tool having a female thread; an uppermember attachable to a running-in string; a lower member telescopicallyrelated to said upper member; expansible and retractable latch meanscarried by and movable laterally of said lower member, said latch meanshaving a male thread engageable with said female thread, said latchmeans being retractable on said lower member to the extent in which theeffective outer diameter of said male thread is less than the innerdiameter of said female thread; means providing a connection betweensaid lower member and latch means for transmitting rotary motiontherebetween; means providing a connection between said upper and lowermembers for transmitting rotary motion therebetween; and a compressionspring engaging said members to urge said lower member and latch meansin an upward direction relative to said upper member.

6. In subsurface apparatus: a well tool having a female thread; an uppermember attachable to a running-in string; a lower member telescopicallyrelated to said upper member; expansible and retractable latch meanscarried by and movable laterally of said lower member, said latch meanshaving a male thread engageable with said female thread, said latchmeans being retractable on said lower member to the extent in which theetfective outer diameter of said male thread is less than the innerdiameter of said female thread; means providing a connection betweensaid lower member and latch means for transmitting rotary motiontherebetween; means providing a connection between said upper and lowermembers for transmitting rotary motion therebetween; a compressionspring engaging said members to urge said lower member and latch meansin an upward direction relative to said upper member; and seal meansbetween said upper and lower members to prevent fluid from passing fromthe interior of said members to the exterior of said members both whensaid members are in fully contracted and fully extended positions withrespect to each other.

References Cited in the le of this patent UNITED STATES PATENTS2,262,117 Roe Nov. ll, 1941 2,318,167 Knowlton May 4, 1943 2,644,524Baker July 7, 1953

1. IN SUBSURFACE APPARATUS: A WELL TOOL HAVING A THREAD; AN UPPER MEMBERATTACHED TO A RUNNING-IN STRING; A LOWER MEMBER TELESCOPICALLY RELATEDTO SAID UPPER MEMBER; EXPANSIBLE AND RETRACTABLE LATCH MEANS CARRIED BYAND MOVABLE LATERALLY OF SAID LOWER MEMBER, SAID LATCH MEANS HAVING ATHREAD COMPANION TO SAID WELL TOOL THREAD AND ENGAGEABLE THEREWITH, SAIDLATCH MEANS BEING MOVABLE LATERALLY IN ONE DIRECTION ON SAID LOWERMEMBER INTO THREADED ENGAGEMENT WITH SAID WELL TOOL THREAD AND LATERALLYIN THE OTHER DIRECTION ON SAID LOWER MEMBER TO AN EXTENT SUFFICIENT TOPOSITION SAID THREADS OUT OF ENGAGEMENT WITH EACH OTHER TO ENABLE SAIDLATCH MEANS TO BE MOVED LONGITUDINALLY AND WITHOUT ROTATION PAST SAIDWELL TOOL THREAD; MEANS PROVIDING A CONNECTION BETWEEN SAID LOWER MEMBERAND LATCH MEANS FOR TRANSMITTING ROTARY MOTION THEREBETWEEN; MEANSPROVIDING A CONNECTION BETWEEN SAID UPPER AND LOWER MEMBERS FORTRANSMITTING ROTARY MOTION THEREBETWEEN; AND MEANS URGING SAID LOWERMEMBER AND LATCH MEANS IN AN UPWARD DIRECTION RELATIVE TO SAID UPPERMEMBER.